A vertical transistor is known, which controls electric current flowing in a direction crossing a substrate surface. The vertical transistor connects, for example, an interconnection on the substrate and an interconnection thereabove, and controls the electric current on/off, which flows through the interconnections. When such transistors are placed on the substrate with higher density, spacing between the gate electrodes of the adjacent transistors is narrowed, and increases the gate to gate capacity. Thus, the vertical transistors have slower switching speed, and make it difficult to respond to high speed signals.